Insulated coil for electrical apparatus and process of making the same.



1 0 6 84 CROSS REFERENCE EXAMINER No. 824,048. PATENTED JUNE 19, 1906.

r I l E. THOMSON. d INSULATED COIL FOR ELECTRICAL APPARATUS AND PROGESS OF MAKING /7 THE SAME. g urmcurox FILED snr'r. 11, 1903.

Witnesses. Inventor- Elihu Thomson 2 by W M fltty.

' coil possessing these characteristics and also UNITED STATES PATENT OFFICE.

ELII-IU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

lNSLlLATED COIL FOR ELECTRICAL APPARATUS AND PROCESS OF MAKING THE SAME.

Specification of Letters Patent.

Patented June 19, 1906.

Application filed September 11, 1903. Serial No. 172-789.

chusetts, have invented certain new and useful Improvements in Insulated Coils for Electrical Apparatus and Processes of Making the Same, of which the following is a specification.

This invention relates to electrodynamic apparatus; and its ob'ect is to provide an im proved magnet-coil't erefor which is strong and simple in construction, thoroughly insulated, and capable of withstanding a high temperature.

To this end the invention consists'in a new in the process of manufacturing said coil, as hereinafter set forth, and particularly pointed out in the claims.

The accompanying drawing is a perspective view of a coil made in accordance with-my invention.-

In'order to obtain a stron and rigid structure, the coil is composed o a s' 1e helix of a flat or ribbon conductor, prefei' afily copper, wound edgewise with the turns close together, so that it forms a tube the thickness of whose wall is the width of the ribbon conductor. After the coil is wound and while there is still somespace between the convolutipnsitiscaversimfsmhmbyiimmersion, w'n ia iinsu atingands m ntiegse pauns consisting of a sihcious substance, pr erably kaolin andsilicategi soda. The proportions of these two mgredients may be varied to some extent, but must be such that the mix m: e is a fluid or viscous liquid, like a water va iish, which will'soak into' all crevices and form a thin layer between the metal coils. The entire coil is then closed ether to form a solid rigid structure and is t en subjected to a high temperature, preferably a low red heat, until the insulating compound is vitrified into an insoluble moisture-proof cement which binds the coils together without permitting contact between its turns. This msulation is a double silicate of aluminium and sodium and is refractory, being incapable of complete fusion except at a temperature which would melt the metal conductor. It is not necessary for it to have the same coeflicient of expansion as the metal conductor, since it becomes somewhat soft at a high temperature. In-plac'e of the kaolin (aluminium silicate) I may use other silicates, such as magnesium silicate, or even finely-powdered silica.

This coil has been es ecially designed for arc-lam s but it is capa 1c of use in any location w ere it must withstand excessive moisture or high'temperature, or both.

What I claim as new, and desire to secure by Letters Patent of the United States, 1s-

1. A coil for electrical apparatus, consisting of an edgewise-wpund fiat conductor whose convdlutrons are insulated from each other and cemented together by a compound of silicious matter and.silicate of soda.

2. A coil for electrical apparatus, consisting of an edgewise-wound flat conductor whose convolutlons are insulated and cemented by a compound of kaolin and silicateoi'. soda 3. A coil for electrical apparatus, consisting of an edgewise-wound flat conductor whose convolutions are insulated and cemented by a vitirified compound of kaolin and slhcate of so a.

A 4. The process of making a coil for electrical apparatus, which consists in winding edgewise a flat metallic conductor, coverlng it with a liquid compound of kaolin and sihcate of soda, closing the.coil.together, and heatin it to vitrify the compound.

5. T e process of making a coil for electrical ap aratus which consists in. windmga fiat meta lic conductor e'dg'ewise into an 0 en helix, immersing it in a hq uid compoIun' of silicious matter and silicate of soda,'.clos1ng pound.

In witness whereof I have hereunto set my hand this 8th day of September, 1903.

' ELIHU THOMSON.

the helix and heating it to vitrify the com- Witnesses:

DUGALD MoK. McKrLLoP, JOHN J. WALKER. 

